Storage tanks

ABSTRACT

In order to provide both access and venting openings to storage vessels, particularly for large quantities of food liquids, which vessels need to be cleaned often, a manway access door is provided with has a partially open stable position which may be used for venting during cleaning. The door is preferably part of a subassembly on its own frame for ease of removal and replacement for repair and maintenance. Spray devices for spraying cleaning liquids inside and outside may be provided.

llnil States latent inventor Alexander Arthur Townsend Crawley, Sussex,England 8419,4155

1 Aug. 12, 1969 Dec. 21, 1971 The A.P.V. Company Limited Crnwley,Sussex, England Aug. 16, 1968 Great Britain 39,286/68 Appl. No. FiledPatented Aasignee Priority STORAGE TANKS 11 Claims, 2 Drawing Figs.

US. Cl. 220/44 R, 134/175, 220/35, 220/57 lnLCl. 136511 51/116, B65d43/16 Field 01 Search ..220/35, 36, 44, 44 A, 57, 55.5, 44 R, 55.3;134/175, 1.77

[56] Meier-emcee Cited UNlTED STATES PATENTS 2,054,145 9/1946 Tandy220/36 X 2,556,354 6/1951 Wiliamson. 220/57 x 2,923,430 2/1960 Stengele220/36 X 3,062,398 1 1/1962 Kordes 220/44 X 3,311,255 3/1967Loveless..... 220/36 3,415,257 10/1968 Wellman 134/175 PrimaryExaminer-George E. Lowrance Attorneyl-llolman & Stern AbSTlRAC'll: Inorder to provide both access and venting openings to storage vessels,particularly for large quantities of food liquids, which vessels need tobe cleaned often, a manway access door is provided with has a partiallyopen stable position which may be used for venting during cleaning. Thedoor is preferably part of a subassembly on its own frame for ease ofremoval and replacement for repair and maintenance.

, Spray devices for spraying cleaning liquids inside and outside may beprovided.

alszagsev PATENTED M1221 ran SHEET 1 BF 2 INVENTOR ALEXANDER ARTHURTOWNSEND illi/ BY /%n44- ATTORNEYS PATENTED 05:21 ran 352 15 7 SHEET 2BF 2 .vl In FIG. 2.

l N V E N TO R AUEXANDER ART H UR T02 NSEND ATTORNEYS BACKGROUND OF THEINVENTION This invention relates to storage tanks and the like and moreparticularly to a device for venting such a storage tank to atmosphere,especially during cleaning operations.

It is common practice to provide large atmospheric vents in storagetanks so that, when hot liquid is admitted to a cold tank or cold liquidto a hot tank, an unacceptably high or low pressure is not created inthe tank by the heating or cooling of air therein or by condensation ofvapors. This is important, particularly since storage vessels are notnormally designed to withstand an internal vacuum, i.e. externalpressure, and the pressure variations generated by these phenomena areoften large enough to cause substantial damage to such tanks. Thisproblem is particularly severe in vessels which are used for holdingfood products or other products requiring that the tank should becleaned at frequent intervals. Such cleaning is commonly performed byadmitting rinsing water and hot detergent solutions to the vessel. Sucha vessel is therefore submitted to alternate heating and cooling bydetergent solutions and rinse water. The rinse waters and detergents arealso commonly applied to the vessel by means of a spraying mechanismoperating under considerable pressure. This means that the changes intemperature may be particularly sudden.

In order to provide the necessary venting action, it is usual to fitvessels that are to be subjected to these conditions with a vent in theroof. Such a vent may be up to 12 inches (30 cm.) or more in diameter.

It is also common for vessels of this type to be fitted with a manwaydoor to enable periodic internal inspection and cleanmg.

Both these fittings require considerable reinforcement to the tank wallin their immediate vicinity, and in order to obtain adequate rigidityare usually themselves of substantial construction.

SUMMARY OF THE INVENTION The present invention consists in a manwayaccess door assembly including a door for attachment to a storage vesselmeans for mounting the door in closed position and means for opening thedoor to a partially open position for purposes of venting the vessel,the door being adapted to open further to allow access to the interiorof the vessel, a splash plate adapted to partially close the aperturewhen the door is in closed and partially open positions, and meansconnecting the splash plate to the door for movement therewith beyondthe partially open position.

Preferably, means are provided for maintaining the plane of the doorsubstantially parallel to the aperture during opening to the partiallyopen position.

The door may be fitted with cleaning devices for spraying cleaning andrinsing liquids on the inside and outside surfaces thereof when in thepartially open position. The inside cleaning device, which may be aspray ball, may be fitted with a nonreturn valve to prevent escape ofliquid from the tube when the level of liquid stored is above the levelof the door. Such a door may also have a plate to prevent liquid sprayedagainst the outside surface from splashing out of the door aperture inthe vessel.

Conveniently, the door is power operated for opening to the partiallyopen position against the action of a closing spring, and releasablefrom the power operating means for manual further opening.

In one convenient embodiment, the whole door and power operating deviceare mounted on a frame which is adapted to be attached to a suitablyreinforced aperture in the storage vessel.

The invention will be further described with reference to theaccompanying drawings, which show a preferred embodiment oftheinvention, and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. llis a side elevation of one formof door according to the invention in position on the side of the tank;and

FIG. 2 is a horizontal section of the door of FIG. I and an adjacentpart of the tank.

DETAILED DESCRIPTION OF THE DRAWINGS The door 1 illustrated is mountedon a separate subassembly on its own frame 2 adapted to be attached bystuds 3 to a suitable reinforcing flange 4 welded around an aperture ina tank 5 (only a small portion of which is shown in the drawings). Agasket 6 is inserted between the frame 2- and flange d. The frame has achannel section extension 7 which carries pivot pins 8 and 9 for thedoor 1 and an operating cylinder-piston unit 10 respectively. The pin 8carries a hinge 11 which sup ports the door by means of a bifurcated end12 receiving one end ofa column 13 pivoted by a pin M. The door 1normally seats on a flat seat surface 15 on the frame 2 with theinterposition ofa sealing ring 16.

The door is raised off its seat surface 15 by means of the cylinder 10,which is a single-acting pneumatic cylinder, and it is normally heldagainst the seat surface 15 by closing springs contained inside thecylinder 10. The stroke of the cylinder 10 is such as to move the dooraway from the seat surface 15 for purposes of venting, but it is notintended that this cylinder 10 should provide sufficient opening formanual access.

Mounted on the column 13 are four radial arms 17. Four bolts 18 passthrough the extremities of these arms and are attached to an annularsplash plate 19,. so that springs 20 surrounding the bolts will urge theplate against a seating surface of the frame 2. It should be noted thatthe stroke of the cylinder 10 is not sufficient to free the plate 19from the frame 2. By means of this assembly, the column 13 is guided sothat the door 1 is maintained parallel to the wall of the vessel 5 inthe immediate vicinity of the door aperture and an even annular gap 21is thus provided round its edge.

The tank is thus vented through the gap 21 and an aperture 22 centrallyof the plate 19.

The column 13 supports a hollow spindle 23 to which the door I and areinforcing and locating collar 24 are welded. The inner end of thehollow spindle carries a spray ball 25 and a nonreturn valve 26, loadedby 'a spring 27 anchored to a cross pin 28, prevents back leakage ofliquid from the vessel into the hollow spindle 23. An inlet connection29 provides for the supply of cleaning and rinsing liquids to the hollowspindle 23. The column 13 has a flange: 30 defining a cavity 31 aroundthe spindle 23 and a nozzle element 32 is lockable on the spindle 23 bymeans of a setscrew to provide an annular nozzle 33 of adjustable widtharound the cavity 31, which is fed with cleaning and rinsing solutionsby means of an inlet connection 34. The cleaning and rinsing solutionsare supplied by means of suitable flexible hoses.

These solutions issue through the valve 26 into the spray ball 25 andare then sprayed into the vessel. This provides cleaning action for themajor area of the door while the annular area around the perimeter ofthe outer surface of the door which is masked by the door itself fromthe spray ball 25, is cleaned by means of the annular nozzle 33.

Plate 19 is also designed to prevent spray from the nozzle 33 fromescaping through the door aperture while the back (outer surface) of thedoor 11 is being cleaned by the spray.

Fitted to the extension 7 are two microswitches 35 (only one of which isvisible in the drawing) which detect the position of the hinge 11. Theseswitches detect respectively the open and closed positions of the hinge,and are used to interlock the movement of the door with the cleaningcontrol system where this is automatic.

When it is required to use the door for access to the interior of thevessel, air is applied to the cylinder 10, to release the tension of theinternal spring, and a pin 36 is withdrawn from the hinge assembly andthe door 1 is then free to be swung into the interior of the vessel. Inthis case, the plate 19 will of course move the door. The presence orabsence of the pin 36 may be detected by an electric or pneumatic switchwhich may be used as a further interlock in the cleaning control system.

By forming the door and its frame as a complete subassembly, the wholearrangement may be easily removed for repair or maintenance andreplaced.

Various modifications may be made within the scope of the invention.Thus the microswitches 35 may be replaced by pneumatic controls. Also,the cylinder may be hydraulically operated, or may be replaced by anelectrical operating mechanism.

lclaim:

1. In a manway access door assembly comprising a door for attachment inan aperture in' a storage vessel, means for mounting the door in closedposition, and means for opening the door to partially open position forpurposes of venting the vessel, the door being adapted for furtheropening to allow access to the interior of the vessel, the improvementincluding a splash plate adapted to partially close the aperture whenthe door is in closed and partially opened positions, and meansconnecting the splash plate to the door for movement therewith beyondthe partially open position.

2. The manway access door assembly as claimed in claim 1, comprisingswitch means for detecting the partially open and the closed positionsof the said door.

3. The manway access door assembly as claimed in claim 1, includingpower means for opening the door in which the door is releasable fromthe power means for manual further opening.

4. The manway access door assembly as claimed in claim 1, in which saidmounting means includes a column to which the door is fixed and meansfor constraining the column to move in a fixed relationship to theaperture during the opening to the partially open position.

5. The manway access door assembly as claimed in claim 1 comprising aspray device extending through the splash plate and door and supportedin part by the means connecting the splash plate to the door forspraying the inside surface of the door with cleaning liquids and aflow'passage passing through the door for supplying cleaning liquids tothe spraying device.

6. The manway access door assembly as claimed in claim 5, including anon return valve in the passage for preventing leakage of liquid fromwithin the tank down the passage.

7. The manway access door assembly as claimed in claim l, including aspray device between the splash plate and the door supported in part bythe means connecting the splash plateto the door for spraying cleaningliquids at the outside of the door.

8. The manway access door assembly as claimed in claim 1 comprising acolumn on which the door is mounted and in which the splash platecooperates with the column to maintain the door in parallel relationshipto the aperture during opening to the partially open position, and saidplate being movable with the door to a position clear of the apertureduring said further opening.

9. The manway access door as claimed in claim 1, comprising aframe,'said door said maintaining means and said closing means beingmounted on the frame to form a sub assembly for attachment to the vesseladjacent the aperture.

10. The manway access door assembly as claimed in claim 1 comprising aseating surface for the splash plate, and spring means urging the splashplate against the seating surface, the spring means serving asconnectors between the splash plate and the door and functioning tomaintain the plane of the door substantially parallel with the apertureduring opening to the partiallyopen position.

11. The manway access door assembly as claimed in claim 10 including acolumn on which the door is mounted, a set of radial arms mounted on thecolumn and individual springs acting between the arms and the splashplate to urge the splash plate onto the seating surface and to maintainthe arms and the door parallel with the seating surface when the door isbetween the closed and partially open positions.

1. In a manway access door assembly comprising a door for attachment inan aperture in a storage vessel, means for mounting the door in closedposition, and means for opening the door to partially open position forpurposes of venting the vessel, the door being adapted for furtheropening to allow access to the interior of the vessel, the improvementincluding a splash plate adapted to partially close the aperture whenthe door is in closed and partially opened positions, and meansconnecting the splash plate to the door for movement therewith beyondthe partially open position.
 2. The manway access door assembly asclaimed in claim 1, comprising switch means for detecting the partiallyopen and the closed positions of the said door.
 3. The manway accessdoor assembly as claimed in claim 1, including power means for openingthe door in which the door is releasable from the power means for manualfurther opening.
 4. The manway access door assembly as claimed in claim1, in which said mounting means includes a column to which the door isfixed and means for constraining the column to move in a fixedrelationship to the aperture during the opening to the partially openposition.
 5. The manway access door assembly as claimed in claim 1comprising a spray device extending through the splash plate and doorand supported in part by the means connecting the splash plate to thedoor for spraying the inside surface of the door with cleaning liquidsand a flow passage passing through the door for supplying cleaningliquids to the spraying device.
 6. The manway access door assembly asclaimed in claim 5, including a non return valve in the passage forpreventing leakage of liquid from within the tank down the passage. 7.The manway access door assembly as claimed in claim 1, including a spraydevice between the splash plate and the door supported in part by themeans connecting the splash plate to the door for spraying cleaningliquids at the outside of the door.
 8. The manway access door assemblyas claimed in claim 1 comprising a column on which the door is mountedand in which the splash plate cooperates with the column to maintain thedoor in parallel relationship to the aperture during opening to thepartially open position, and said plate being movable with the door to aposition clear of the aperture during said further opening.
 9. ThemaNway access door as claimed in claim 1, comprising a frame, said doorsaid maintaining means and said closing means being mounted on the frameto form a sub assembly for attachment to the vessel adjacent theaperture.
 10. The manway access door assembly as claimed in claim 1comprising a seating surface for the splash plate, and spring meansurging the splash plate against the seating surface, the spring meansserving as connectors between the splash plate and the door andfunctioning to maintain the plane of the door substantially parallelwith the aperture during opening to the partially open position.
 11. Themanway access door assembly as claimed in claim 10 including a column onwhich the door is mounted, a set of radial arms mounted on the columnand individual springs acting between the arms and the splash plate tourge the splash plate onto the seating surface and to maintain the armsand the door parallel with the seating surface when the door is betweenthe closed and partially open positions.